The present invention relates to a physiological monitoring device including means for generating an alarm signal in the event the physiological function rate falls above or below preset limits and for displaying the alarm condition.
Electronic equipment has been used to monitor the physiological body functions of a patient such as in the intensive care facility of hospitals. The body functions may, for example, comprise diastolic and mean blood pressures, heart rate, and the like. It has also been known to provide such units with integral alarm circuits so that in the event the physiological function deviates from preset bounds, an alarm is activated.
Heretofore, upon activation of such an alarm, it has been the duty of the medical attendant to scrutinize the monitor device closely and to make a determination of what change in the physiological function triggered the alarm. In most instances, this may be determined by noting the illumination of small front panel lamps. However, this requires that the attendant return to the instrument and note the meter reading and lamp status, to determine whether the alarm was triggered as a result of too high or too low a reading.
In addition, it is possible for an alarm to be triggered by one extreme and thereafter fall to a completely opposite extreme before the attendant has an opportunity to view the display. For example, in a case where the patient's heartbeat rate is being monitored his condition could be such that the heartbeat rate changes from an overly high rate situation (ventricular tachycandin) to an overly low rate situation (cardiac arrest) in a very short period of time before an attendant would have an opportunity to view and analyze the display. The attendant viewing the display at the time of cardiac arrest would, probably, have no way of knowing that the cardiac arrest was preceded by a high rate situation.
In view of the above, it is the principal object of the present invention to provide a physiological function display device adapted to not only indicate the numerical value of the physiological function at any time but also to indicate whether the value exceeds or falls below preselected limits in an error-proof and extremely visible manner.
A further object is to provide such a device with memory capabilities so that in the event an alarm is triggered, the condition which first triggered the alarm is preserved whether the function returns to a normal condition or even swings to the opposite extreme.